Thermal regenerators

ABSTRACT

A thermal regenerator of the kind having a rotary disc-type matric enclosed in a casing traversed by two segregated flows of gaseous heat-exchanging fluids is equipped with an annular flexibly mounted counterface sealing element which makes rubbing contact with the corresponding face of the matrix, and which, in cross-section, has an asymmetric profile tapering from maximum thickness adjacent to the high-pressure side of the sealing element to minimum thickness at the low-pressure side.

United States Patent Barnard 1 Nov. 21, 1972 [541 THERMAL REGENERATORSef ences Cited [72] Inventor: Mark Cary Sedgwick Barnard, UNITED STATESPATENTS Kemlwmth England 2,398,783 4/1946 Gilbert, Sr ..277/96 R x [73]Assignees Leyland Gas Turbines Limited, 2,980,452 4/1961 Cahill eta]...277/42 Solihun, E gl d 3,234,999 2/1966 Atwood ..l/9 [22] Filed: July1971 Primary Examiner-Albert W. Davis, Jr. [21] App]. No,; 159,925Att0rneyHolcombe, Wetherill & Brisebois [30] Foreign APP! E 9nP 9EiE RL![57] ABSTRACT Aug. 15,1970 Gr t B i i 39 1 A thermal regenerator of thekind having a rotary disc-type matric enclosed in a casing traversed bytwo segregated flows of gaseous heat-exchanging fluids is [52] US. Cl./9, 277/43, 277/88, equipped with an annular flexibly mounted counter-277/96 face sealing element which makes rubbing contact [51] Int. Cl..F28d 19/04 with the corresponding face of the at a w ch, 58 Field ofSearch ..l65/9; 277/42, 43, 88, 96 R, in cross-section, has anasymmetric Profile tapering 277/96 A from maximum thickness adjacent tothe high-pressure side of the sealing element to minimum thickness atthe low-pressure side.

3 Claims, 1 Drawing Figure THERMAL REGENERATORS This invention relatesto thermal regenerators (otherwise known as regenerativeheat-exchangers) of the kind employing a moving matrix, e.g. a rotarydisctype matrix.

Thermal regenerators of the kind referred to are usually incorporated ingas turbine power plants to extract heat from the exhaust gases, and totransfer it to the compressed intake-air before this enters thecombustion chamber of the gas turbine engine. The rotary disc-typematrix norm ally employed, which is housed in the casing of the engine,comprises a foraminous refractory core (e.g. of ceramic or glass-ceramicmaterial) formed with a multitude of open-ended, thinwalled passageslying substantially parallel to its rotational axis. Sector-like zonesof the core are caused (by its rotation) to be presented alternately tothe flow of the exhaust gases and to the flow of the compressedintake-air. In that way the required heat transference is effected.

It is, of course, necessary to segregate the two gaseous flows at alltimes, and to minimize leakage between the high-pressure zone, occupiedby the compressed intake-air, and the low-pressure zone occupied by theexhaust gases. The usual practice is to employ an annular sealingelement which makes rubbing contact with the corresponding face of thematrix, and which is mounted on a flexible member fixed to the casing ofthe engine. The intended purpose of the flexible member is to maintaincontact between the matrix face and the counterface of the sealingelement despite differential movements that occur between the enginecasing and the matrix under operating conditions, and despite wear ofthe counterface of the sealing element.

It is convenient to mount the sealing element on a support ring which issecured to the flexible member. The support ring itself is sufficientlyflexible around its periphery to accommodate general distortions, but isless able to accommodate local distortion (particularly when this occursacross the sealing counterface).

According to this invention a thermal regenerator, of the kind having arotary disc-type matrix enclosed in a casing which is traversed by twosegregated flows of gaseous heat-exchanging fluids, is equipped with anannular flexibly mounted counterface sealing element which makes rubbingcontact with the corresponding face of the matrix, and which, incross-section, has an asymmetric profile tapering from maximum thicknessadjacent to the high-pressure side of the sealing element to minimumthickness at the low-pressure side. This purposeful configuration of thesealing element not only assists its bedding-in process but alsoconduces to more uniform seal-loading, and reduces the overall rate ofwear.

With the improved design of sealing element, the seal-loading is highwhere initial peripheral contact occurs. As wear takes place, the loadper unit area (and hence the rate of wear) is reduced for two reasons;namely, (a) because the actual rubbing area has increased, and (b)because the high-pressure area of the pressure profile-under the sealhas increased, thus bedding-in processhas been completed.

he accompanying drawing IS a schematic fragmentary sectional plan viewexemplifying how a sealing element in accordance with the invention isapplied to a rotary-disc regenerator of a gas turbine engine.

In the embodiment illustrated, a gas turbine engine has its casing 1arranged to enclose a rotary disc-type matrix 2 of a thermalregenerator. When the engine is running, two segregated flows ofgaseous'heat-exchanging fluids traverse the casing l, and hence also thethermal regenerator. The latter is equipped with a flexibly mountedcounterface sealing element 3 of annular form, which makes rubbingcontact with the corresponding face of the matrix 2. The sealing element3 is made of nickel oxide.

In cross-section, the sealing element 3 has an asymmetric profile and,as shown, is of substantially wedgelike shape. It tapers from maximumthickness adjacent to the high-pressure low-temperature side (i.e. zone4) of the sealing element 3 to minimum thickness at the low-pressurehigh-temperature side (i.e. zone 5). Adjacent to its thicker outerperiphery, which is at zone 4, the sealing element 3 has a small flat 6at its maximum thickness where initial peripheral contact with thematrix face occurs.

The sealing element 3 is mounted on a support ring 7, of ferritic steel,which is fixed to one end of a convoluted annular flexible sheet metalmember 8; the other end of this flexible member being firmly attached tothe engine casing l by means of an intervening annular plate 9 which isbolted (as at 10) to the casing l. The preferred material for the member8 is the nickelbased alloy known as Nimonic (Nimonic" is a Trade Mark).

lclaim:

1. A thermal regenerator of the kind having a rotary disc-type matrixenclosed in a casing which is traversed by two segregated flows ofgaseous heat-exchanging fluids; characterized by being equipped with anannular flexibly mounted counterface sealing element which makes rubbingcontact with the corresponding face of the matrix, and which, incross-section, has an asymmetric profile tapering from maximum thicknessadjacent to the high-pressure side of the sealing element to minimumthickness at the low-pressure side.

2. A thermal regenerator according to claim 1, in which the sealingelement is of substantially wedge-like shape in cross-section and,adjacent to its thicker outer periphery at the high-pressure side, has asmall flat at its maximum thickness where initial peripheral contactwith the matrix face occurs.

3. A thermal regenerator according to claim 1, in which the sealingelement is mounted on a support ring which is fixed to one end of aconvoluted annular flexible sheet metal member that has its other endfirmly attached to the engine casing.

1. A thermal regenerator of the kind having a rotary disc-type matrixenclosed in a casing which is traversed by two segregated flows ofgaseous heat-exchanging fluids; characterized by being equipped with anannular flexibly mounted counterface sealing element which makes rubbingcontact with the corresponding face of the matrix, and which, incross-section, has an asymmetric profile tapering from maximum thicknessadjacent to the highpressure side of the sealing element to minimumthickness at the low-pressure side.
 1. A thermal regenerator of the kindhaving a rotary disc-type matrix enclosed in a casing which is traversedby two segregated flows of gaseous heat-exchanging fluids; characterizedby being equipped with an annular flexibly mounted counterface sealingelement which makes rubbing contact with the corresponding face of thematrix, and which, in cross-section, has an asymmetric profile taperingfrom maximum thickness adjacent to the high-pressure side of the sealingelement to minimum thickness at the low-pressure side.
 2. A thermalregenerator according to claim 1, in which the sealing element is ofsubstantially wedge-like shape in cross-section and, adjacent to itsthicker outer periphery at the high-pressure side, has a small flat atits maximum thickness where initial peripheral contact with the matrixface occurs.